This invention relates to a method of extracting environmental contaminants and pollutants through biomass harvestation, and in one particular aspect through the harvestation, and enzymatic digestion of animals and animal tissue into basic organic components.
At an alarming rate a wide variety of persistent pollutants and contaminants are being introduced into our environment. Such pollutants are often the result of industrial processes, agricultural endeavours, or other aspects of human existence in an increasingly populated world. In other cases the sources of pollutants or contaminants may be natural as elements that are toxic to plant and/or animal life may sometimes naturally exist in native rock, soil and water. While the existence of pollutants and contaminants is of concern regardless of where they are found, persistent pollutants in bodies of water can be particularly detrimental to plants, animals and humans alike. Pollutants also tend to accumulate in bodies of water as toxic materials introduced into the atmosphere or soil often end up in bodies of water by way of precipitation, run-off, or through general ground water contamination.
Once a body of water becomes contaminated with a pollutant it often becomes difficult to purge that pollutant from the water system. Typically organic pollutants become concentrated in aquatic life and vegetation living within the water body. The concentration of pollutants tends to be higher in fish and animal life that exist higher up the food chain, to the extent that some aquatic life living in polluted bodies of water may themselves represent toxic materials within the definition of environmental protection and anti-pollution legislation. Higher life forms, and in particular predatory life forms, generally have the effect of extracting a portion of organic pollutants or contaminants from the environment through feeding on lower life forms that themselves have extracted pollutants from the water and/or underlying soil. However, once the higher life forms die and decompose the pollutants become reintroduced into the aquatic environment and begin to slowly make their way back up the food chain. A natural cycle is thus created that, if left on its own, has little chance of removing pollutants from the body of water. Most often the rate of the addition of pollutants far exceeds the ability of nature to purge them from a body of water, causing the water to slowly become more and more polluted.
Even where concerted efforts are made to reduce the amount of pollution added to a particular body of water or eco-system, such efforts have little impact or effect on reducing the contaminant load within the food chain of that ecosystem. Without a means to capture the contaminant materials and effectively eliminate them from the eco-system, the contaminants and pollutants will continue to cycle through the food chain and will continue to taint and affect organisms, including man. Currently, the recovery of biomass for contaminant capture is frustrated and inefficient due to the relatively large volume of water and other organic material that must be disposed of along with the contaminants. Disposing of biomass material is also wasteful from the perspective that valuable constituents and nutrients that may be contained within organisms are destroyed or disposed of along with the contaminants. Finally, and as indicated above, there are some situations where organisms from an eco-system are so severely contaminated that they themselves must be treated as a hazardous waste, which may prevent the depositing of such materials in landfills or may significantly increase the cost of their disposal and/or methods of destruction.
The invention therefore provides a method for selectively extracting pollutants or environmental contaminants from an ecosystem by means of biomass harvestation and subsequent processing. The method has as one of its underpinnings the realization that many pollutants and contaminants are persistent within an ecosystem due to the inability of living organisms to break them down. As a result, pollutants and contaminants often tend to accumulate and become concentrated within life forms that are higher up in the food chain such that the concentration of such materials in some cases can be several thousand times greater in high trophic-level predators than within the surrounding environment.
Accordingly, in one of its aspects the invention provides method for extracting contaminants and pollutants from an ecosystem, the method comprising the steps of (i) extracting from the ecosystem a quantity of animal tissue; (ii) grinding or macerating said animal tissue to form a slurry-like mixture and adding said mixture to a digestion vessel; (iii) reducing the pH of said ground animal tissue to a range of from approximately 3.5 to approximately 4.5 and allowing said ground tissue to decompose through the action of digestive enzymes released from the visceral tissue of said animal tissue by said maceration step; (iv) separating said decomposed tissue into a lipid portion, a proteinaceous portion and a bone fragment or hard tissue portion; and, (v) extracting at least a part of said lipid portion from said decomposed tissue for further processing or disposal of contaminants and pollutants contained therein.
In a further aspect the invention provides A method for concentrating and extracting environmental contaminants and pollutants from a body of water, the method comprising the steps of (i) extracting from the body of water a quantity of fish or other aquatic life forms; (ii) grinding or macerating said fish or aquatic life forms to form a slurry of ground tissue and adding said ground tissue to a digestion vessel; (iii) reducing the pH of said slurry of ground tissue to a range of approximately 3.5 to approximately 4.5 and allowing said slurry of ground tissue to decompose through the action of digestive enzymes released from visceral tissue of said fish or aquatic life forms by said maceration step; (iv) separating said decomposed tissue into a lipid portion, a proteinaceous portion and a bone fragment or hard tissue portion; and, (v) extracting at least a part of said lipid portion from said decomposed tissue for disposal or for further processing of contaminates and pollutants contained therein.
The invention further provides a method for concentrating and extracting environmental contaminants from an ecosystem, the method comprising the steps of (i) collecting and extracting from the ecosystem a quantity of animals or animal tissue; (ii) grinding or macerating said animals or animal tissue to form a slurry-like mixture of ground animal tissue and adding said ground tissue to a digestion vessel; (iii) adding to said slurry of ground animal tissue a carbohydrate and maintaining said ground tissue in said digestion vessel at a temperature of between approximately 8xc2x0 C. and 35xc2x0 C. to encourage fermentation, said fermentation causing a build up of acid such that as the pH of said ground animal tissue drops to below 4.5 said tissue decomposes through the action of digestive enzymes released from visceral tissue of said animals by said maceration step; (iv) separating said decomposed tissue into a lipid portion, a proteinaceous portion and a bone fragment or hard tissue portion; and, (v) extracting at least part of said lipid portion from said decomposed tissue for further processing or disposal of contaminants contained therein.
Further aspects and advantages of the invention will become apparent from the following description taken together with the accompanying drawings.